PPT Slide
7 – Sequential Logic Examples
Highway/farmroad intersection with car sensors for farmroad
- busy highway, little used farmroad
- detectors C sense the presence of cars waiting on the farmroad
- if no car on farmroad (FR), light remains green for highway (HW)
- If car on FR, HW lights go from G to Y to R, then FR lights can go to green
- FR lights stay green only as long as there are cars on FR but no longer than a pre-defined interval
- when no more cars on FR, FR lights go from G to Y to R, then HW lights can go to green.
- even if FR vehicles are waiting, HW lights stay green for a pre-defined minimum time
assume you have an interval timer that generates: a short time pulse (TS) and a long time pulse (TL), in response to a set (ST) signal.
TS is to be used for timing yellow lights and TL for green lights